Wideband angle-of-arrival location determination using bandwidth partitioning

Abstract

Techniques are presented herein for improving location determination of a wireless device in environments where there can be multipath issues. A wireless device having a plurality of antennas receives a wireless transmission from a target device whose location is to be determined. Channel state information data is generated based on reception of the transmission at the plurality of antenna. The channel state information data is separated or partitioned into subcarrier group specific data for each of a plurality of groups of subcarriers within a bandwidth of the received transmission. Location probability data is computed for each of the plurality of groups of subcarriers from the subcarrier group specific data for respective ones of the plurality of groups of subcarriers. The location probability data for the plurality of groups of subcarriers is combined to produce aggregate location probability data, from which a location of the target device is determined.

What is claimed is: 
     
       1. A method comprising:
 receiving at a wireless device having a plurality of antennas, a wireless transmission from a target device whose location is to be determined; 
 at the wireless device, generating channel state information data at a plurality of groups of subcarriers within a frequency bandwidth of the wireless transmission based on reception of the transmission at respective ones of the plurality of antennas of the wireless device; 
 separating the channel state information data into subcarrier group specific data for each of the plurality of groups of subcarriers within the frequency bandwidth of the wireless transmission; 
 computing subcarrier group specific location probability data for each of the plurality of groups of subcarriers from the subcarrier group specific data for respective ones of the plurality of groups of subcarriers; 
 combining the subcarrier group specific location probability data for the plurality of groups of subcarriers to produce aggregate location probability data; and 
 determining a location of the target device from the aggregate location probability data. 
 
     
     
       2. The method of  claim 1 , wherein receiving, generating and separating are performed for each of a plurality of wireless devices that receives the wireless transmission from the target device, each of the plurality of wireless devices having a plurality of antennas, so as to produce, for each of the plurality of wireless devices, subcarrier group specific data for each of the plurality of groups of subcarriers. 
     
     
       3. The method of  claim 2 , wherein computing comprises computing, for each of the plurality of wireless devices, subcarrier group specific location probability data for each of the plurality of groups of subcarriers from the subcarrier group specific data for respective ones of the plurality of groups of subcarriers. 
     
     
       4. The method of  claim 3 , wherein combining comprises combining the subcarrier group specific location probability data for the plurality of subcarrier groups across the plurality of wireless devices to produce the aggregate location probability data. 
     
     
       5. The method of  claim 1 , wherein combining includes summing the subcarrier group specific location probability data for the plurality of groups of subcarriers. 
     
     
       6. The method of  claim 1 , wherein combining includes performing a maximum likelihood computation based on the subcarrier group specific location probability data for the plurality of groups of subcarriers. 
     
     
       7. The method of  claim 1 , wherein combining includes adding a correlation between measured phases and expected phases for a location. 
     
     
       8. The method of  claim 1 , wherein combining includes adding a sum of squared error between measured phases and expected phases for a location. 
     
     
       9. The method of  claim 1 , wherein generating and separating are performed at the wireless device, and further comprising sending the subcarrier group specific data for each of the plurality of groups of subcarriers to a server, and wherein computing subcarrier group specific location probability data, combining the subcarrier group specific location probability data and determining the location of the target device are performed at the server. 
     
     
       10. The method of  claim 1 , wherein each group of subcarriers comprises a contiguous set of adjacent subcarriers. 
     
     
       11. A system comprising:
 a device including:
 a plurality of receivers, each associated with a corresponding one of a plurality of antennas; and 
 a network interface unit that enables network communication; 
 a processor coupled to the plurality of receivers, wherein the processor is configured to:
 generate channel state information data at a plurality of groups of subcarriers within a frequency bandwidth of a wireless transmission based on reception, at respective ones of the plurality of antennas, of the wireless transmission from a target device whose location is to be determined; 
 separate the channel state information data into subcarrier group specific data for each of the plurality of groups of subcarriers within the frequency bandwidth of the wireless transmission; and 
 
 
 a server configured to:
 receive, via the network interface unit, the subcarrier group specific data from the device; 
 compute subcarrier group specific location probability data for each of the plurality of groups of subcarriers from the subcarrier group specific data for respective ones of the plurality of groups of subcarriers; 
 combine the subcarrier group specific location probability data for the plurality of groups of subcarriers to produce aggregate location probability data; and 
 determine a location of the target device from the aggregate location probability data. 
 
 
     
     
       12. The system of  claim 11 , wherein each group of subcarriers comprises a contiguous set of adjacent subcarriers. 
     
     
       13. The system of  claim 11 , wherein the processor is configured to compute subcarrier group specific location probability data for each of the plurality of groups of subcarriers from the subcarrier group specific data for respective ones of the plurality of groups of subcarriers. 
     
     
       14. The system of  claim 13 , wherein the processor is configured to combine the subcarrier group specific location probability data for the plurality of groups of subcarriers to produce aggregate location probability data. 
     
     
       15. The system of  claim 11 , wherein the server is configured to combine the subcarrier group specific location probability data for the plurality of groups of subcarriers by summing the subcarrier group specific location probability data for the plurality of groups of subcarriers. 
     
     
       16. The system of  claim 11 , wherein the server is configured to combine the subcarrier group specific location probability data for the plurality of groups of subcarriers by performing a maximum likelihood computation based on the subcarrier group specific location probability data for the plurality of groups of subcarriers. 
     
     
       17. The system of  claim 11 , wherein the server is configured to combine the subcarrier group specific location probability data by adding a correlation between measured phases and expected phases for a location. 
     
     
       18. The system of  claim 11 , wherein the server is configured to combine the subcarrier group specific location probability data by adding a sum of squared error between measured phases and expected phases for a location. 
     
     
       19. A non-transitory computer readable storage media encoded with instructions that, when executed by a processor, cause the processor to perform operations comprising:
 computing subcarrier group specific location probability data for each of a plurality of groups of subcarriers that spans a frequency bandwidth of a wireless transmission received at respective ones of a plurality of antennas of a wireless device from a target device whose location is to be determined, the subcarrier group specific location probability data being computed from channel state information for individual ones of the plurality of groups of subcarriers based on reception of the wireless transmission at the plurality of antennas of the wireless device; 
 combining the subcarrier group specific location probability data for the plurality of groups of subcarriers to produce aggregate location probability data; and 
 determining a location of the target device from the aggregate location probability data. 
 
     
     
       20. The non-transitory computer readable storage media of  claim 19 , wherein the instructions operable for computing subcarrier group specific location probability data is performed for each of a plurality of wireless devices that receives the wireless transmission from the target device, each of the plurality of wireless devices having a plurality of antennas, so as to produce, for each of the plurality of wireless devices, subcarrier group specific data for each of the plurality of groups of subcarriers. 
     
     
       21. The non-transitory computer readable storage media of  claim 20 , wherein the instructions operable for combining comprise instructions operable for combining the subcarrier group specific location probability data for the plurality of subcarrier groups across the plurality of wireless devices to produce the aggregate location probability data. 
     
     
       22. The non-transitory computer readable storage media of  claim 19 , wherein the instructions operable for combining comprise instructions operable for summing the subcarrier group specific location probability data for the plurality of groups of subcarriers. 
     
     
       23. The non-transitory computer readable storage media of  claim 19 , wherein the instructions operable for combining comprise instructions operable for performing a maximum likelihood computation based on the subcarrier group specific location probability data for the plurality of groups of subcarriers. 
     
     
       24. The non-transitory computer readable storage media of  claim 19 , wherein the instructions operable for combining comprise instructions operable to add a correlation between measured phases and expected phases for a location. 
     
     
       25. The non-transitory computer readable storage media of  claim 19 , wherein the instructions operable for combining comprise instructions operable to add a sum of squared error between measured phases and expected phases for a location. 
     
     
       26. The non-transitory computer readable storage media of  claim 19 , wherein each group of subcarriers comprises a contiguous set of adjacent subcarriers.